Trajectory-based interpretation of laser light diffraction by a sharp edge

In the diffraction pattern produced by a half-plane sharp edge when it obstructs the passage of a laser beam, two characteristic regions are noticeable. There is a central region, where it can be noticed the diffraction of laser light in the region of geometric shadow, while intensity oscillations are observed in the non-obstructed area. On both sides of the edge, there are also very long light traces along the normal to the edge of the obstacle. The theoretical explanation to this phenomenon is based on the Fresnel-Kirchhoff diffraction theory applied to the Gaussian beam propagation behind the obstacle. Here we have supplemented this explanation by considering electromagnetic flow lines, which provide a more complete interpretation of the phenomenon in terms of electric and magnetic fields and flux lines, and that can be related, at the same time, with average photon paths.Comment: 13 pages, 5 figure

Fuzzy model for predicting the number of deformed wheels

Deformation of the wheels damage cars and rails and affect on vehicle stability and safety. Repair and replacement cause high costs and lack of wagons. Planning of maintenance of wagons can not be done without estimates of the number of wheels that will be replaced due to wear and deformation in a given period of time. There are many influencing factors, the most important are: weather conditions, quality of materials, operating conditions, and distance between the two replacements. The fuzzy logic model uses the collected data as input variables to predict the output variable - number of deformed wheels for a certain type of vehicle in the defined period at a particular section of the railway

Changes in Crude Protein Content with Advancing Maturity in Lucerne

The main determinants of the quality of lucerne forage are digestibility and protein content (Julier et al., 2001) as well as crude fibre content. In the early vegetative phases, the crude protein content of the leaves and stems is the highest and crude fibre content the lowest (Katic et al., 2003). The aim of this study was to determine the rate of change in crude protein levels at different stages of growth and development

Application of multifractal analysis on microscopic images in the classification of metastatic cancer intraoseal

mikroskopskih medicinskih slika s ciljem njihove klasifikacije, u smislu utvrðivanja primarnog karcinoma u slucajevima intraosealnih metastatskih karcinoma. Dosadašnja saznanja ukazuju da postoji razlika u morfologiji zdravih i kancerogenih celija. Prethodni rezultati, izloženi u magistarskom radu kandidatkinje „Klasifikacija digitalnih medicinskih slika primenom multifraktalne analize“ [ANDJ06], i primenjeni u klasifikaciji slika karcinoma kolona, otvorili su mogucnosti za dalja istraživanja i moguce primene multifraktalne analize na mikrofotografije uzoraka drugih tkiva. S obzirom da su, u slucaju razlicitih vrsta primarnih karcinoma, celije cesto neregularnog ("haoticnog") oblika, utvrðivanje eventualne korelacije izmeðu multifraktalnih parametara koji opisuju oblik celija i primarnih karcinoma, moglo bi imati veliku primenu. Ocekuje se da multifraktalna analiza omoguci definisanje objektivnih pokazatelja kojima se može izvršiti klasifikacija tkiva. Multifraktalna analiza u klasifikaciji primarnog karcinoma, kao pomocni alat, mogla bi ubrzati proces odlucivanja i doprinela smanjenju subjektivnog faktora i verovatnoce greške pri dijagnozi.The aim of this study was to determine statistically significant differences between microscopic medical images in order of their classification in terms of determining primary cancer in cases of metastatic carcinoma intraoseal. Past findings indicate that there is a difference in the morphology of healthy and cancerous cells. Preliminary results, presented in the magisterium thesis of the candidate, „Classification of digital medical images using multifractal analysis“ [ANDJ06], and applied to classify images of colon cancer, opened the possibility for further investigation micrographs of samples of other tissues. Since, in the case of different types of primary cancer cells are often of irregular ("chaotic") forms, determining the possible correlation between multifractal parameters describing the shape of primary cells and the cancer, could have broad application. It is expected that multifractal analysis enables the definition of objective indicators that can performed tissue classification. In the classification of primary tumors, the multifractal analysis, as an assistant tool, could accelerate the decision-making process and contribute to reduction of subjective factors and error probability in medical diagnosis

Teorijsko-metodološki problemi revizije finansijskih izveštaja turističkih preduzeća

U promenljivom okruženju od revizora se ne traži da overi istorijske informacije u finansijskim izveštajima klijenta, već da gleda u budućnost i da bude spreman da drži korak s promenljivim potrebama javnosti, kao i s promenama u korporativnoj strukturi, finansijskom tržištu, informatičkim i komunikacionim tehnologijama. Investitori traže bolju zaštitu, veći kvalitet informacija (u smislu tačnosti i pravovremenosti) za finansijsko tržište, veću odgovornost i kontrolu nad postupcima korporativnih rukovodilaca i revizorskih firmi. U skladu sa promenama u turbulentnom okruženju i zahtevima investitora svakako da revizori specijalisti za pojedine delatnosti (npr. ugostiteljstvo, turizam, osiguranje i slično) mogu kvalitetnije odgovoriti ovim promenama i zahtevima. Uvažavajući predmet i cilj istraživanja, postavljene hipoteze i primenjene metode istraživanja u disertaciji su analizirani teorijsko-metodološki problemi revizije turističkih preduzeća. Eksterni revizori, koji bolje poznaju delatnost ugostiteljstva i turizma, spremniji su da definišu kvalitetniji plan revizije i da na efikasan i efektivan način obave proces revizije iz razloga dobrog poznavanja vrsta usluga koje se pružaju u ovim preduzećima i standardizovanog načina knjigovodstvenog obuhvatanja ovih usluga. Kroz disertaciju istraživanje je usmereno na identifikovanje usluga pomenutih delatnosti, način njihovog obuhvatanja u poslovnim knjigama, ukazano na specifičnosti forme i sadržine finansijskih izveštaja ovih preduzeća i na kraju analizirani problemi koji se mogu javiti prilikom revizije finansijskih izveštaja turističkih preduzeća. Identifikovane su specifične bilansne pozicije u turističkim preduzećima polazeći od vrste I obima usluga koje se pružaju. Prestavljene su procedure revizorskih ispitivanja specifičnih bilansnih pozicija ugostiteljskih i turističkih preduzeća. Eksterni revizor izražavanjem mišljenja o finansijskim izveštajima ugostiteljskih ili/i turističkih preduzeća daje najviši nivo uveravanja licima koja su zainteresovana za finansijske informacije ovih preduzeća.The changing environment is not required from the auditor to certify the historical information in the financial statements the client, but to look to the future and be prepared to keep pace with the changing needs of the public, as well as changes in corporate structure, financial markets, information and communication technologies. Investors want better protection, higher quality information (in terms of accuracy and timeliness) for the financial markets, greater responsibility and control over the actions of corporate executives and audit firms. In accordance with the changes in the turbulent environment and requirements of investors certainly auditors specialists for specific activities (eg, catering, tourism, insurance and the like) can better respond to these changes and requirements. Taking into account the object and purpose of the research, hypotheses and research methods applied in the dissertation analyzes the theoretical and methodological problems in revision of tourism enterprises. External auditors who know better catering and tourism activity are more likely to define the high- quality audit plan and to efficiently and effectively carry out the audit process because a good knowledge of the types of services provided in these companies and standardized ways of accounting includings these services. Throughout the thesis we focused research on identifying the services mentioned activities, way of their including in business accounting books, showed the specific form and content of the financial statements of these companies and ultimately analyzed the problems that may arise during the audit of the financial statements of tourism enterprises. They identified specific balance sheet items in the tourist business starting from the type and volume of services provided. Audit testing procedures specific balance sheet items in catering and tourism companies are presented. The external auditor is expressing an opinion on the financial statements or hospitality / tourism enterprises and provides the highest level of assurance to persons who are interested in financial information to these companies

Effect of Mineral Nutrition on Red Clover Leaf Area Index

The legume red clover (Trifolium pratense) fixes its own nitrogen (N), but requires P and K fertilisation. There are no recent reliable data in the domestic literature, on the amounts of P and K recommended to farmers; present recommendations are often either inadequate or excessive. Red clover mineral nutrition is significantly affected by soil and weather conditions (Taylor & Quesenberry, 1996). The objective of our twoyear study was to enable rational fertiliser application in accordance with soil type and agro ecological conditions

Agronomic Characteristics of Novi Sad Winter Vetch Cultivars

Genus Vicia. contains important annual food and forage species such as field bean, V. faba., narbon vetch, V. narbonensis, and common vetch, V. sativa (Maxted, 1995), while Hungarian V. pannonica Crantz and hairy vetch V. villosa also play an important role in the Balkans. Winter vetches are excellent forage catch crops useful for sustainable agriculture and organic farming (Ċupina et al., 2004). Our study was aimed at determining the agronomic characteristics of the winter vetch cultivars developed in Novi Sad, assessing thus their ability for successful growing in the prevailing conditions of Serbia and Montenegro

Polymerase chain reaction in the identification of periodontopathogens: A reliable and satisfactory method?

Aggregatibacter actinomycetemcomitans is considered one of the bacterial species of etiological importance in periodontitis. The aim of this study was to evaluate the serotype of A. actinomycetemcomitans in the subgingival biofilm in subjects with periodontal health and disease. Pooled samples of subgingival plaque were taken for culture-based identification of microorganisms. Colonies suspected to be A. actinomycetemcomitans were selected for molecular identification using either multiplex or conventional PCR in serotype-specific genotyping and 16S rRNA gene sequencing. In silico analysis showed that most selected colonies belong to the genus Campylobacter, although positive signals for serotypes of A. actinomycetemcomitans were obtained with these samples. Identification of A. actinomycetemcomitans by conventional PCR for 16S rRNA with one species-specific and one universal primer was inconclusive because an almost identical signal with Campylobacter gracilis was obtained. Although PCR-based methods for the identification of A. actinomycetemcomitans are more rapid, sequencing should not be omitted. [Projekat Ministarstva nauke Republike Srbije, br. 41008 and br. 173048

Polymerase chain reaction in the identification of periodontopathogens: A reliable and satisfactory method?

Aggregatibacter actinomycetemcomitans is considered one of the bacterial species of etiological importance in periodontitis. The aim of this study was to evaluate the serotype of A. actinomycetemcomitans in the subgingival biofilm in subjects with periodontal health and disease. Pooled samples of subgingival plaque were taken for culture-based identification of microorganisms. Colonies suspected to be A. actinomycetemcomitans were selected for molecular identification using either multiplex or conventional PCR in serotype-specific genotyping and 16S rRNA gene sequencing. In silico analysis showed that most selected colonies belong to the genus Campylobacter, although positive signals for serotypes of A. actinomycetemcomitans were obtained with these samples. Identification of A. actinomycetemcomitans by conventional PCR for 16S rRNA with one species-specific and one universal primer was inconclusive because an almost identical signal with Campylobacter gracilis was obtained. Although PCR-based methods for the identification of A. actinomycetemcomitans are more rapid, sequencing should not be omitted

ZnTiO3 Ceramic Nanopowder Microstructure Changes During Compaction

ZnTiO3 nanopowder as a constitutive component in compact production was primarily characterised. Scanning electron micrographs of as received powder were recorded. Mercury porosimetry and nitrogen adsorption were also performed on loose powder. Particle size distribution in a water powder suspension was determined with a laser particle size analyser. Compaction was performed on different pressures in a range from 100 to 400 MPa using the uniaxial double sided compaction technique without binder and lubricant. Micrographs of compacted specimens were obtained using scanning electron microscopy and atomic force microscopy. Pore size distribution was also determined by mercury porosimetry and nitrogen adsorption. Results revealed that with increasing pressure during compaction interagglomerate pores diminish in size until they reach some critical diameter related to the intra-agglomerate pore size